1. Field of the Invention
The present invention relates to an image processing apparatus, an image recording apparatus, a method for controlling the same, and a power supply apparatus used therein.
2. Related Background Art
Presently, in general, an image recording apparatus such as a printer indispensably requires a dual-output power supply which combines a large-capacity engine driving power supply (e.g., of 24V) for use in a steady operation and a small-capacity engine controlling power supply (e.g., of 3.3V).
Recently, in particular, there have been developed various technologies for saving energy in a wait state in a specific attempt to save on power in a wait state (during sleeping) in which the engine driving power supply is not necessary.
FIG. 1 is a circuit diagram showing one example of a configuration of a power supply system for an electrophotographic image recording apparatus by the present inventor. In this drawing, a reference numeral 1 indicates a commercial AC power supply, an alternating current from which is rectified by a diode-bridge 2, a direct current from which is in turn smoothed by a capacitor 3 and then supplied to two converters.
That is, reference numerals 10 and 110 indicate respective transformers of these converters, being provided with primary windings 27 and 127, secondary windings 28 and 128, and control windings 29 and 129, respectively, in such a configuration that the primary windings 27 and 127 have switching-element MOSFET""s 7 and 107 connected thereto, respectively. On the side of the primary winding of the converter, reference numerals 4 and 104 indicate driving circuits comprised of controlling IC""s for turning the respective FET""s 7 and 107 ON and OFF and reference numerals 5 and 105, the respective resistors. On the side of the secondary winding of the converter, reference numerals 16 and 116 indicate rectifying diodes and reference numerals 20 and 120, smoothing capacitors, in such a configuration that one of the two converters which is installed at the upper stage feeds out +24V DC voltage and the other converter at the lower state, +3.3V DC voltage.
The controlling windings 29 and 129 for the converters have connected thereto rectifying diodes 9 and 109, smoothing capacitors 8 and 108, and resistors 6 and 106 respectively, thus supplying their DC outputs (Vcc) to driving circuits 4 and 104 respectively. The driving circuits 4 and 104 also have connected thereto photo-transistors of photo-couplers 12 and 112 respectively, in such a configuration that the anodes of light emitting diodes of the photo-couplers 12 and 112 are connected via resistors 23 and 123 to output terminals of the primary winding respectively, while the cathodes have constant-voltage diodes 24 and 124 respectively, gates of which are supplied with outputs (ref) of the secondary side output voltage divided by resistors 21 and 22 and resistors 121 and 122 respectively.
In FIG. 1 again, a reference numeral 200 indicates an engine controller for the image recording apparatus and a reference numeral 300 indicates a relay for cutting off the power supply, a relay coil of which is connected with a transistor 301 controlled by the engine controller and a relay contact of which is connected to a heating means 400 of a fixing device and also between a triode AC switch (triac) and the commercial power supply. A reference numeral 600 indicates a relay for cutting the power supply, a relay contact of which is disposed on a DC power supply input line on the primary winding side of the upper stage converter and a relay coil of which is connected to a transistor 601 controlled by the engine controller 200.
In the circuit of the above-described configuration, if the heating means 400 or the triac 500 fails, the relay 300 acts to prevent the AC power supply from being applied to the heating means 400. In such a case, the engine controller 200 turns the transistor 301 ON and OFF to open and close the relay 300. The engine controller 200 also drives and controls the printer engine, the heater driving circuit for controlling a quantity of electrification through the heater of the heating means, and the relays 300 and 600.
The relay 600 acts to cut off power to the 24V power supply, while the engine controller 200, in a constant lapse of time after the relevant printer terminates printing and enters the wait state, turns OFF the transistor 601 in order to open the relay 600, thus cutting off power to the 24V power supply. To restart actual printing, that controller turns ON the transistor 601 to close the relay 600, thus supplying power to the 24V power supply.
With such a configuration, the relay 600 can be opened in the wait (sleep) state to cut off power supplied to the 24V power supply, thus saving on power in that state.
An image recording apparatus which employs the above-described power-supply circuit has many circuit components used for cutting the power supply, which leads to such problems of an increased cost, an expanded packaging surface, and an enlarged apparatus.
There may also be such a method of, in the sleep state, changing an oscillation frequency to permit the power supply to engage in blocking oscillation, in order to lower the voltage level of the driving power supply, thus reducing the loss of energy required.
An example of such control method of blocking oscillation is described below with reference to FIGS. 2 and 3.
FIG. 2 shows an example of a circuit configuration of a power supply apparatus by the present inventor for a printer etc. Note here that the same reference numbers indicate the same parts in FIGS. 1 and 2.
The reference number 200 indicates the engine controller, which drives the printer engine, controls the engine, the heater driving circuit for controlling a quantity of electrification through the heater, and the relays.
This engine controller 200 is provided with three ports of an RLDR port connected to a cutting-off control circuit for the relay 300, an FCHG port connected to a frequency control circuit for a power supply control IC 4, and a VCHG port connected to a power-supply voltage control circuit.
The engine controller 200 sets the RLDR port High and Low to turn the transistor 301 ON and OFF, thus opening and closing the relay 300.
A reference numeral 212 indicates a photo-coupler for transmitting a signal generated from the FCHG port of the engine controller 200 to the power-supply control IC 4, thus changing for a frequency of the power-supply control IC 4. Furthermore, to obtain a 3.3V output Vcc2 from the 24V output Vcc1, three-terminal regulators 150 and 151 are provided, as well as a resistor 152 and a transistor 153 for switching Vref.
(Sleep state)
The following will describe operations in the sleep state.
When the printer terminates printing, the engine controller 200 sets the FCHG port Low, thus cutting off a current flowing through the photo-coupler 212 in a constant lapse of time (in the sleep state). With this, the FCHG port of the power-supply control IC 4 is connected to GND via a point P.
In this sleep state, as shown in FIG. 3, the oscillation frequency of the power-supply control IC 4 is decreased, thus reducing a switching loss of the power supply.
Furthermore, the engine controller 200 sets the VCHG port Low to turn OFF the transistor 153, thus cutting off electrification to the resistor 152. With this, the power supply is controlled such that a voltage obtained by dividing a Vcc1 voltage with feedback resistors 21 and 22 may be equal to a reference voltage of a shunt regulator 24.
When a current flows at the light emitting section of the photo-coupler 12, the light emitting section is turned ON to permit the current to flow out of the F.B section of the power-supply control IC 4. In response to this current, the power-supply control IC 4 controls its own duty ratio, thus stabilizing power supply.
In such a sleep state, the voltage Vcc1 becomes about 6V. At the same time, the voltage Vcc2 generated by a diode 116 and a capacitor 120 may be about 0.8V but actually becomes 3.2V because of a 3.2V power supply applied via the three-terminal regulator 150 and the diode 151.
(Steady state)
The following will describe operations in the steady state.
To enter a printing state, the engine controller 200 sets the VCHG port High to turn ON the transistor 153 in order to conduct the resistor 152, thus immediately returning the voltage Vcc1 value to 24V. At the same time, it sets the RLDR port High to turn ON the transistor 301, thus closing the relay 300.
Then, at predetermined timing, the engine controller 200 drives the printer engine and controls the engine itself and a quantity of electrification to the heater, thus permitting printing.
The engine controller 200, however, must be provided with the three ports of RLDR, FCHG, and VCHG, so that it needs to have circuits corresponding to these ports.
This leads to increases in the number of engine controller ports for power supply control in the sleep state and the number of the circuit components, accompanied by various problems of an enlarged apparatus size and an increased cost due to increases in the packaging surface area.
In view of the above, it is an object of the present invention to provide an image processing apparatus, an image recording apparatus, a method for controlling the same, and a power supply apparatus used in the same which can save on power dissipation in the wait state while reducing the number of parts required, the packaging surface area, and the apparatus size.
It is another object of the present invention to provide an inexpensive and small-sized image processing apparatus, image recording apparatus, and power supply apparatus used therein by decreasing the number of ports of the engine controller and the number of its components.
An image recording apparatus related to the present invention comprises: image recording controlling means for controlling image recording operations; a multiple-output power supply having plural converters for generating a driving voltage for image recording from an external power supply; and cutting-off means for cutting off supplying power from the above-described external power supply, wherein according to a cutting-off signal sent from the above-described image recording controlling means, the operating power for at least one of the above-described converters is cut off by the above-described cutting-off means.
Another image recording apparatus related to the present invention comprises: image recording controlling means for controlling image recording operations; a multiple-output power supply having plural converters for generating a driving voltage for image recording from an external power supply; and cutting-off means for cutting off supplying of power from the above-described external power supply, wherein according to a cutting-off signal sent from the above-described image recording controlling means, at least one of the above-described converters is stopped in operation by the above-described cutting-off means.
An image recording apparatus controlling method related to the present invention controls still another image recording apparatus related to the present invention comprising: image recording controlling means for controlling image recording operations; a multiple-output power supply having plural converters for generating a driving voltage for image recording from an external power supply; and cutting-off means for cutting off supplying of power from the above-described external power supply, wherein according to a cutting-off signal sent from the above-described image recording controlling means, operating power for at least one of the above-described converters is cut off by the above-described cutting-off means.
In the above-described image recording apparatus, preferably, operating power for the converter which feeds a driving voltage to the fixing device is cut off by the above-described cutting-off means.
Another embodiment of the present invention is directed to an image recording apparatus controlling method for controlling still another image recording apparatus comprising: image recording controlling means for controlling image recording operations; a multiple-output power supply having plural converters for generating a driving voltage for image recording from an external power supply; and cutting-off means for cutting off supplying of power from the above-described external power supply, wherein according to a cutting-off signal sent from the above-described image recording means, at least one of the above-described converters is stopped in operation by the above-described cutting-off means.
In the above-described image recording apparatus, preferably, operating power for the converter that feeds a driving voltage to the fixing device is cut off by the above-described cutting-off means.
The present invention provides an advantage of reducing a power loss in the wait state as well as a packaging surface area to decrease the apparatus size and its cost.
A power supply apparatus according to the present invention changes the power of a driving power supply based on frequency control. The apparatus includes power supply controlling means for controlling, in response to a change in the frequency, the power of the driving power supply generated by an external power supply; image processing controlling means for controlling an image processing apparatus to which power of the above-described driving power supply is supplied; and driving controlling means for changing the frequency of the above-described power supply controlling means according to a cutting-off controlling signal for cutting off the power supply which is output from the above-described image processing controlling means to the above-described image processing apparatus.
In this case, the above-described driving controlling means may change the above-described frequency of the above-described power supply controlling in a blocking manner.
The above-described driving controlling means may involve a wait operation whereby the above-described frequency is changed in a blocking manner and a steady operation whereby the above-described frequency is changed continuously.
The above-described driving controlling means may change the power supply voltage of the above-described driving power supply.
An image processing apparatus according to the present invention is supplied with power based on frequency control, and comprises the above-described power supply apparatus and image processing means for processing images using power with a controlled frequency fed out from that power supply apparatus.
The above-described image processing means may image recording means for recording images.
The above-described cutting-off controlling signal output from the above-described power supply apparatus can be output to fixing means of the above-described image recording means.
A method of power supply control according to the present invention actually changes the power of the driving power supply, and comprises the steps of: controlling the power of the driving power supply generated from the external power supply corresponding to a change in the frequency; controlling the image processing apparatus to which the power of the above-described driving power is supplied; and controlling the power supplied to the above-described driving power supply, by changing the above-described frequency.
A method for processing images according to the present invention actually processes images by supplying frequency-controlled power, and comprises the steps of: using the above-described power supply controlling method to output power which is changed according to frequency control; and processing images according to the output power.
According to the present invention, a power-supply cutting-off signal output from, for example the engine controller to a printer acts also as the frequency controlling signal, to change the frequency of the power supply control IC in order to vary a voltage value of the driving power supply, so that the cost due to an energy loss in the wait state can be reduced. Also, because the number of the ports of the engine controller can be reduced, the packaging surface area for the power supply apparatus can also be reduced to make the apparatus more compact.
According to the present invention, moreover, when the cutting-off means for cutting off the supply of power fed from an external power supply to a load is in a cut-off state, at least one of the outputs of a multiple-output power supply is inhibited. Therefore, by interrelating the controlling of the above-described load and the controlling for inhibiting the above-described at least one output of the power supply other than that load, the apparatus can be simplified in terms of configuration and control.
Other objects and features of the present invention will become apparent from the following detailed description and the attached drawings.